A material such as glass, a metal or a resin is used for an ink jet recording head.
In the use of a water-based ink in an ink jet recording head, when the water repellency of the surface of a nozzle is unsatisfactory, droplets of an ink are liable to adhere to the surface of the nozzle, which spoils the rectilinearity of jetted ink droplets, so that it often becomes impossible to conduct recording due to occurrence of troubles such as disturbance of setting.
For this reason, the surface of a nozzle which is a portion for jetting an ink has hitherto been subjected to a treatment for rendering the surface of the nozzle water-repellent. For example, a proposal has been made on a method wherein a particle of a water-repellent material is deposited on the surface of a nozzle, for example, by electrostatic powder coating (see Japanese Patent Application Laid-Open No. 157765/1982) and vacuum deposition and plasma polymerization (see Japanese Patent Application Laid-Open Nos. 183161/1985 and 176059/1984) to render the surface of the nozzle water-repellent.
In the above-described conventional treatment for rendering the surface of the nozzle water-repellent, it is not always easy to form a smooth repellent surface free from any defect such as a pinhole. This causes properties to be varied from product to product, and the properties to change with the elapse of time. Further, in the electrostatic powder coating, the baking temperature should be 300.degree. C. or above. In the case of a metal, the dimensional accuracy is spoiled, and it is impossible to apply this method to a resin. When use is made of vacuum deposition, a large device should be used and it is difficult to conduct the process control. Further, in this method, since the bonding strength is insufficient, only a product having an insufficient bonding strength can be obtained.
The present invention can solve the above-described problem, and an object of the present invention is to provide an ink jet recording head which is excellent in the water repellency of the surface of the nozzle, the persistence of the water repellency and the durability and enables a high printing quality to be maintained for a long period of time, and a process for producing the same.